1. Field of the Invention
This invention relates to the analysis of images created via an x-ray source. More particularly, the invention relates to digitizing an x-ray film and analyzing its image.
2. Discussion of the Related Art
Different solids absorb x-rays, a type of electromagnetic radiation, at different rates. A photographic plate behind an object may record the amount of x-rays passing through the object or scattered by it to create a shadow image. The photographic plate is developed and an x-ray image results on a film having varying gray levels of transparency. Typically, these film are 14 inches by 17 inches.
X-ray films made by the above process serve as invaluable tools for those involved in the scientific, medical, and industrial endeavors. Those people reading the x-ray films typically view and analyze the images using a light box or light table for passing light through the x-ray films.
Some of the endeavors require quantitatively analyzing the x-ray film, for example, measuring tumor size in medical applications and ballistic performance in projectile and explosive development application. This type of analyzing requires measuring the size of each feature and comparing that size with predicted results or charting changes in size over a period of time. Currently such measuring is accomplished by hand. For applications in the development of shaped charges, for example, the film measuring and reduction for a single test firing exceeds one manday.
Recent advances in computer technology allow scanning of x-ray films to create digitized files. Various software tools allow applications of a wide range of image enhancements and analytical tools to the digitized x-ray film. For example, software may "pseudo-color" to the gray scale levels in the digitized x-ray image to aid in visual review of the x-ray image.
Another advantage of digitizing is electronic storage and retrieval of x-rays images. Having x-ray images stored on computer accessible media significantly reduces and replaces the physical space required to store x-ray films. Furthermore, the time necessary to retrieve an x-ray image from computer accessible media is negligible compared to physical retrieval of an x-ray film. Additionally, due to today's ease of computer interconnectivity, the actual physical location of the digitized files may be different from the location where the x-ray image is viewed or analyzed.
Several systems and methods for digitizing x-ray films are known. Typically, these systems capture a video image and then make a conversion from analog to digital. The video image is created by a plurality of charge-coupled devices (CCDs) in either a one dimensional or two dimensional array.
The one dimensional array includes a plurality of CCDs aligned along a single line. In such an arrangement, the linear array or the film must travel relative to each other. This traveling is one source of noise or error in digitizing the film.
The two dimensional array typically assumes a fixed square field of view and so has an N.times.N array of CCDs, where N is the number of CCDs in one direction. Square arrays of CCDs are not conducive to scanning a fourteen by seventeen inch x-ray film.
Since the scanning rate and area for both arrays are fixed, neither array allows users to scan a selected portion of a film in a resolution higher than that for the whole scan area.
These typical scanning systems scan the x-ray films in gray scale via the transmissive characteristics of the films and are thus not suited to multiple applications such as those additionally including multi-color reflective transmission from an object.
There is a need for an x-ray film digitizing system that reliably digitizes x-ray film that is simple and cost effective to build and use.
There is also a need for a x-ray film scanning system that reliably digitizes x-ray films with significant reductions in noise and creates a digitized image allowing processing heretofore not contemplated. There is also need new techniques and methods for analyzing digitized x-ray films to provide significant advantages in older, more time consuming method and techniques.